Update default MOTD file

The old MOTD was a bit misunderstandable as it suggested being some
kind of official Debian service. Thanks to Andreas Barth for an
initial suggestion.

debian/ngircd.motd

@@ -1,5 +1,11 @@
 **************************************************
-*              H    E    L    L   O              *
-*    Welcome on our new IRC server, running on:  *
-*    Debian GNU/Linux (www.debian.org)           *
+*             H    E    L    L    O              *
+*  This is a private irc server. Please contact  *
+*  the admin of the server for any questions or  *
+*  issues.                                       *
+**************************************************
+*  The software was provided as a package of     *
+*  Debian GNU/Linux <http://www.debian.org/>.    *
+*  However, Debian has no control over this      *
+*  server.                                       *
 **************************************************